Plastics incinerator



D2 JQ .1.A. Bovo aux. 31,495,555 PLASTICS INDINERATDR 3 Sheets-Sheet 1 INVENTORS, JOHN A. BDYD DONALD E. DDYD ATTORNEYS IIB DEEE

Feb. 17, 1970 Filed Feb. 23, 196s FIG. 2

3 Sheets-Sheet 2 Feb. 17,- 1970 J. A. amro ETAL PLASTICS INCINERATOR mea Feb. 2s, 196s LEEEEEEEE mmnmmmmmns fzwjjjjj] FIG. 3

INVENToRal JOHN A. BOYD DONALD E. BOYD BY M yw/ ATTORNEYS.

FIG. 4

3 Sheets-Sheet 3 INVENToRs. JOHN A. BOYD DONALD E. BOYD ATTORNEYS.4

BY f' med Feb. 25, 1955 United States Patent O 3,495,555 PLASTICS INCINERATOR John Allison Boyd, Fairfax, and Donald E. Boyd, Clifton,

Va., assignors to Washington Incinerator Sales & Service, Inc., Alexandria, Va., a corporation of the District of Columbia Filed Feb. 23, 1968, Ser. No. 707,560

Int. Cl. F23g 3/00 U.S. Cl. 110-8 11 Claims ABSTRACT OF THE DISCLOSURE An incinerator specially adapted for burning plastic materials in such a manner that the materials are substantially completely burned with a minimum of smoke and odors. Such plastic materials are introduced into a primary combustion chamber Where they are subjected to initial burning, and thereafter, the products of com- This invention relates to the art of incineration and more particularly it relates to an incinerator construction which is capable of, and adapted for, burning various forms of plastic materials which have heretofore been difiicult to dispose of. l In recent times, various forms of plastic materials have come into common usage and such plastic materials have been used for a wide variety of disposable items such as drinking cups, containers, utensils, packaging cushions, etc. One common type of such plastic material which has come into widespread use recently is foamed polystyrene, but the present invention comprehends disposal of all types of plastic materials by incineration thereof. While such plastic items have been intended to yserve as disposable items which can be thrown away after use, difficult problems have arisen in attempting to nally dispose ofsuch plastic materials. If, for example, such plastic materials are merely piled in an outdoor dump, they will remain there for extended periods of time since these plastic materials have very little tendency to decom pose or deteriorate under normal weathering conditions. If it is attempted to crush or grind these plastic materials and subsequently ush or otherwise dispose of the same into the sewage system, problems arise due to the fact that such plastic materials create fouling at theotation stations.

Certainly, the most desirable means for disposing of such plastic materials would be by way of burning or incinerating the same so that such materials are completely reduced to ashes which can then be removed, but prior attempts to burn such plastic materials, and polystyrene foam particularly, have created substantial problems. First of all, it must be recognized that many plastic materials, such as styrene, do not readily burn since they do not readily combine with oxygen. Most plastics used for the purposes described hereinabove are insulators and, as such, are very low conductors of heat. The cellular composition of such plastics, particularly foamed plastics, presents heat and air from reaching beyond the surface layer of the materials. Thus, when prior attempts have been made to burn these materials,

3,495,555 Patented Feb. 17, 1970 ice the result is a partially decomposed mass of plastic which is often sticky, soggy, and ditlicult to handle. Specifically, heating such plastics without oxygen to support burning reduces the polymeric structure of such plastics to a monomer, which, in many plastics, is a liquid in the combustion range and cools to a highly viscous mass at lower temperatures. Secondly, and of equal importance, is the fact that prior attempts to burn such plastic materials have created an extremely black, sooty, smoke which very seriously pollutes the air surrounding the place where the burning is occurring. Thirdly, and still of equal importance, is the fact that the burning of such plastic materials ordinarily gives rise to extremely noxious` fumes and odors which, once again, pollute the atmosphere surrounding the area where the burning is occurring.

With the foregoing in mind, it is, therefore, an object of the present invention to provide a new and improved form of incineration apparatus which will burn and incinerate such plastic materials substantially completely, without producing any undesirable air pollution, either by smoke or by odors or by both.

Another object of the present invention is to provide a plastics incinerator which is fully capable of burning all forms of plastic materials, but which can also burn other substances, such as paper, food waste, etc., which might be mixed with the plastic materials.

Another object of the present invention is to provide a highly efricient incinerator which burns plastic materials that have heretofore cretaed difficult com-bustion problems due to the fact that the materials themselves do not ordinarily support combustion.

Another object of the present invention is to provide an incinerator for plastic materials which assumes basically the same configuration as a conventional incinerator and which can `be used in conjunction with conventional incineration apparatus such as scrubbers, stacks, etc.

Other objects, advantages, and salient features of the present invention will become apparent from the following detailed description which, taken in conjunction with the annexed drawings, discloses a preferred embodiment thereof.

Referring now to the drawings:

FIG. l is a top plan view of one embodiment of incinerator in accordance with the principles of the present invention, shown in section since the top thereof has been removed for purposes of illustration;

FIG. 2 is a longitudinal sectional view of the incinerator of FIG. l, taken substantially along the line 2-2 of FIG. 1;

FIG. 3 is a view similar to that of FIG. 1, but showing another modification of the present invention;

FIG. 4 is a longitudinal sectional view of the incinerator of FIG. 3, taken substantially along the line 4-4 of FIG. 3; and

FIG. 5 is a transverse sectional View taken substantially along the line 5 5 of FIG. 3.

Referring now to the embodiment shown in FIGS. l and 2, there is illustrated therein an incineration apparatus generally designated 20. For convenience, and for ease of illustration, only the refractory or fire brick construction of the incinerator is shown, but it will be understood that, in actual practice, the exterior surfaces thereof are covered by an insulation material and usually by a metal casing as well.

Incinerator 20 includes a pair of spaced parallel side Walls 22 and 24 joined together at their forward end by a front wall 26 and joined together at their rear ends by a rear wall 28. Additionally, as shown in FIG. 2, incinerator 20 is provided with a bottom or base wall 30 and 3 a top wall 32. All of these walls are fabricated of some suitable refractory material, such as fire brick.

A first intermediate wall 34 is disposed in spaced parallel relationship to the front wall 26 and extends transversely across the inciner-ator between side walls 22 and 24 thereof. The space between the front wall 26 and the intermediate wall 34 defines a primary combustion charnber generally designated 36 where initial combustion of the plastic materials takes place. A grate 38 extends across the primary combustion chamber near the lower end thereof to support the plastic material as it is burned in the primary combustion chamber and the ashes or residue therefrom can drop downward beneath the grate and subsequently can be cleaned out by means of a clean-out: door 40 provided -at the lower end of the side wall 24.

The front wall 26 is provided with an opening or charging port 42, the lower surface of which is sloped somewhat downwardly and inwardly into the primary combustion chamber 36. A charging hopper 44, forming a hood or cowl, extends forwardly of the incinerator from the front wall 26 thereof and can be closed by a closure door 46 mounted in any suit-able fashion, such as by suspension from a cable 48.

A first burner means 50 shoots a flame through a passage 52 in the side wall 24 of the incinerator so that the flame is directed into the primary combustion chamber 36, preferably toward the rear central part thereof. A thermostatic control device 54 is mounted in the opposite wall 22 of the primary combustion chamber to control the burner 50 and to cut the same off when the temperature within the primary combustion chamber reaches a predetermined or present amount, which can be suitably adjusted or preset.

At the upper portion of the primary combustion chamber 36, as can be seen in FIG. 2, the upper wall is separated into a pair of superposed layers 56 and 58, spaced apart by a fiow passage 60. The innermost of the layers 56, which forms the top surface of the primary combustion chamber 36, is provided with at least one orifice 62, preferably disposed close to the wall 34 forming the rear wall of the primary combustion chamber. The uppermost wall 58 is provided with an orifice 64 which connects with a fan or blower 66 that directs air through the passage 64 and into the space 60. Part of the air passes through the orifice 62 and into the upper portion of the primary combustion chamber 36, to thereby aid in providing a combustion-supporting atmosphere in the primary combustion chamber. Another portion of the air from the blower 66 passes through the space 60 and is hence somewhat preheated due to the fact that the layer 56 will be hot from the combustion occurring in the primary combustion chamber. This preheated air then exits from the front of the space 60 through a pipe or other suitable conduit 68 which connects to and communicates interiorly with a hollow duct 70 surrounding the hood 44. A series of spaced small ports or apertures 72 are formed through the walls of the hood 44 to communicate the interior of the hood with the interior of the duct 70.

Thus, a portion of the yair provided from the blower or fan 66 will pass through the space 60 where it will be preheated and it will flow through the pipe 68 into the duct 70. Then, it will pass through the apertures or orifices 72 into the interior of the hood 44 and will be directed back inwardly through the charging port 42 into the primary combustion chamber 36 to further support combustion therein. Additionally, this preheated air which is being provided through the orifices 72 -at the charging section of the incinerator 20 serves two further functions. First, this preheated air from the orifices 72 tends to keep the smoke and odors within the primary combustion chamber 36 and prevents the same from escaping back through the charging port 42 sothat when the door 46 is opened to supply additional material to the incinerator, the smoke and odors do not escape through the open door. Secondly, the air emitting through the orices 72 serves to keep the interior region of the hood, particularly at the forward part thereof adjacent door 46, in a cool or relatively cool condition as cornp-ared with the interior of the primary combustion charnber itself. Thus, when an operator opens the charging door 46 to supply new plastic materials through the charging hopper and into the primary combustion chamber, such plastic materials do not immediately melt as they are being introduced, but instead, remain relatively rigid until they actually reach the primary combustion chamber 36. Still further, it will be remembered that the flame from the burner 50 was directed essentially toward the medial portion of the rear wall 34 in the primary combustion chamber, and the air emitting through the orifices 72 aids in directing the combustion -gases within the primary combustion chamber 32, which have entrained soot, fly ash and other combustible particles, toward this ame area at the rear of the primary combustion chamber. Furthermore, the air from the orifices 72 creates rapidly moving air currents in the primary combustion chamber 32 to cause a turbulent condition which moves the burning mass therewithin to expose the inner surfaces and under layers of the mass to, contact with air and to radiant heat radiating from the walls of the chamber.

In the embodiment shown in FIGS. 1 and 2, the wall 34 is provided with a port 74 in the upper right-hand corner thereof, when looking front to rear, and the products 0f combustion from the primary combustion chamber 36 are directed therethrough as indicated by the arrows in FIGS. 1 and 2. The orifice 62 is preferably located adjacent the port 74 so that a certain amount of air from the blower 64 will admix with the products of combustion as they pass from the primary combustion chamber through the port 74.

Another wall 76 extends transversely across the incinerator 20, between the side walls 22 and 24 thereof, with the wall 76 being spaced rearwardly a selected distance from the wall 34. The space created between the walls 34 and 76 defines a secondary combustion chamber which is generally designated 78, and as the products of combustion pass through the port 74, they enter this secondary combustion chamber, A diffusion chamber fmeans is provided centrally of the secondary combustion chamber 78 to set the same off into left-hand and righthand portions. The diffusion chamber means includes a pair of spaced apart walls 80 and 82 extending generally axially of the incinerator and hence substantially perpendicularly between the walls 34 and 76 which define the limits of the secondary combustion chamber. The side walls 80 and 82 are joined together by end walls 84 and 86, the former of which is notched or recessed in the wall 34 and the latter of which is notched or recessed in the wall 76, such construction being used for structural integrity. The walls 80, 82, 84 and 86 thus Serve to circumscribe and define a diffusion chamber means and hence set off a vertically extending diffusion chamber 88 extending therebetween.

The walls 80 and 82 are provided with a staggered series of openings 90 therein, as can best be seen from FIG. 2, thus creating a checkerboard arrangement by which the chamber 88 communicates with the outer portions of the secondary combustion chamber 78.

Before continuing with the description of the secondary combustion chamber, it seems worthwhile to note at this point that a third or tertiary combustion chamber generally designated 92 is provided. The combustion chamber 92 is set off between the wall 76 and a further wall 94 extending transversely between the side walls 22 and 24 of the incinerator, rearwardly of the wall 76. Another diffusion chamber means, substantially identical with that previously described, is provided medially or centrally of the tertiary combustion chamber 92. Specifically, this diffusion chamber means includes a pair of spaced side walls 96 and 98 joined by a pair of end walls 100 and 102, the former of which is notched or recessed into the wal] 76 and the latter of which is notched or recessed into the wall 94. Thus, a vertically extending diffusion chamber or shaft 104 is provided centrally of the tertiary combustion chamber 92. Also, as can best be seen from FIG. 2, the walls 96 and 98 are provided with a series of spaced, arranged openings 106, similar to the openings 90 in the Walls 80 and 82 in the secondary combustion chamber. Means are provided for introducing ambient air into and through the vertically extending chambers or shafts 88 and 104, and in the illustrated embodiment of FIG. 2, such means includes a wall 108 extending beneath the secondary and tertiary combustion chambers in spaced relation above the base wall 30, to thereby provide a space or passage 110 therebetween. A fan or blower 112 is connected at the end of the passage 110 to introduce ambient air thereinto, and as such air travels through the passage 110, it is preheated due to the fact that the wall 108, or at least that portion thereof between the secondary and tertiary combustion chambers, is elevated in temperature due to the combustion occurring in such chambers. As a result, when the air traverses the passage 110, it contacts against the wall 108 and is thus heated. Openings 114 are provided at the forward end of the passage 110 to exit the air therefrom into the vertically extending chamber 88 in the secondary combustion chamber. Similarly, openings 116 are provided in communication with the vertically extending chamber 104 in the tertiary combustion 'chamber 92. As illustrated, three openings 114 are provided but only two openings 116 are provided, and while the invention certainly need not be limited to this type of arrangement of openings, such arrangement does assure a more or less even distribution of preheated air into the chambers 88 and 104 so that the chamber 104, located nearest the blower 112, does not receive more air than the chamber 88 located furthest therefrom. A second burner 118 is provided along wall 22 at the secondary combustion chamber 78 and flame from this burner passes through an opening 120 in the side wall 22 and is directed into the secondary combustion chamber. A thermostatic control 122 for the burner 118 is also provided in the secondary combustion chamber 78, and looking forwardly to rearwardly, the burner 118 is in the right-hand side of the combustion chamber while the thermostatic control 122 is in the left-hand side thereof. The flame from the burner 118 is directed onto the wall 80 of the diffusion chamber means, and it serves to heat this wall to an incandescent condition. That is, the burner 118 heats the wall 80 to a glowing red hot or white hot condition and such heating is, of course, facilitated by the fact that air is being directed upwardly through the chamber 88 adjacent the opening and such air can partially escape through the openings 90 in the wall 80 to promote heating thereof. It has, in fact, been found that the burner 118 not only heats the wall 80 to an incandescent condition, but additionally, heats the opposite wall 82 to a generally similar incandescent condition.

Thus, the products of combustion from the primary combustion chamber means pass through the ports 74 and into the right-hand side of the secondary combustion chamber 78 whereat they are burned by the flame from the burner 118. Then, they contact the incandescent walls 80 and 82 and pass therethrough to the left-hand side of the secondary combustion chamber 78, and, quite naturally, as they pass through the walls 80 and 82 and the vertically extending chamber 88 therebetween, preheated air admixes with such products of combustion to provide a further combustion-supporting atmosphere which facilitates further burning of these products of combustion. Also, additional burning and combustion of these primary combustion chamber products is accomplished by contacting the same against the incandescent walls 80 and 82 as they must necessarily do to pass through the openings 90 formed therein. As idicated by the arrows, the flow of these combustion products is then directed into the lefthand side of the secondary combustion chamber and through an opening or series of openings 124 formed at the lower left-hand corner of the wall 76, when looking front to rear in the incinerator. As the gases pass therethrough, they then enter the left-hand portion of the tertiary combustion chamber 92.

A third burner means 126 is provided along the side wall 24 of the incinerator adjacent the tertiary combustion chamber 92, and the flame from this burner passes through an opening 128 in the wall 24 and is directed into the tertiary combustion chamber, specifically onto the wall 98 of the diffusion chamber means therein. The burner 126 heats the wall 98 and the wall 96 as well, to an incandescent condition, just as the burner 118 in the secondary combustion chamber heated the walls and 82 to an incandescent condition. Thus, the gases in the tertiary combustion chamber contact against the incandescent wall 98, pass through the openings 106y thereof to admix with the preheated air being introduced through the vertically extending chamber 104, and pass back out through the openings 106 in the incandescent wall 96 to enter the right-hand side of the tertiary combustion chamber 92.

Then, the gases from the tertiary combustion chamber pass through one or more openings 130 at the right-hand side of the wall 94, when looking front to rear in the incinerator, and enter a final settling chamber 132 located between the wall 94 and the rear wall 28 of the incinerator. Any incombustible fragments or particles which still remain in the gas stream at this point settle into the chamber 132 and can ultimately be cleaned out through a clean-out door 134. The gases themselves pass through an opening 136 in the incinerator side wall 24 and are transmitted through a breeching to a chimney or gas washer. If desired, one or more openings can be provided through the slab 108 into the chamber 132 to thereby interconnect the passage with the chamber 132 so that a small amount of ambient air can be introduced thereinto. Such air would assure that any carbon monoxide still present in the gases would be oxidized to produce carbon dioxide as it passes through the opening 136.

While the illustrated apparatus of FIGS. 1 and 2 is not drawn to scale, it has been found in practice that a satisfactory apportionment of the apparatus resides in providing approximately fifteen percent of the volume of the incinerator 20 for the primary combustion chamber 36, y

the remaining eighty-five percent of the volume Ibeing apportioned to the chambers 78, 92 and 132. It will also be noted that in these chambers which follow the primary combustion chamber, which could collectively be referred to as secondary chambers, the products of combustion are directed through a substantial series of right angle turns. As the gases and any particles, fly ash or other material entrained therewith, are transmitted through this series of turns, they are contacted against the incandescent refractory walls surrounding the diffusion chambers as they must necessarily be to pass through the staggered openings in such walls. Naturally, the unburnt constituents in the gases become burned or incinerated as they contact against these incandescent walls. Additionally, during passage through the various secondary chambers, preheated air, supplied through the vertically extending shafts of chambers 88 and 104, admixes with such gases to facilitate and promote further combustion of such gases. It has been found that an arrangement in accordance with the aforementioned description has operated very satisfactorily in the burning of plastic materials which were heretofore difficult, if not impossible, to burn. Specifically, it has been found that the plastic materials, when initially incinerated in the primary combustion chamber 36, creates an extremely thick, acrid, black, sooty smoke having an extremely noxious odor. However, by the time that the products of combustion from the primary combustion chamber have bene directed through the various secondary chambers, contacted against the incandescent walls therein, burned by the further burner means, and admixed with the preheated air, the gases 1eaving through the opening 136 to the breeching are substantially free from odor and are substantially free of any entrained matter. Thus, such gases could be directly transmitted through a stack into the atmosphere without polluting the air surrounding the incinerator 20, although it might be advantageous in most instances to provide a gas Washer or scrubber adjacent the breeching from the opening 136. The thermostatic controls for the primary and secondary burners serve to cut off such burners when the temperature reaches a preselected amount or value.

Referring now to the further embodiment of the invention as shown in FIGS. 3-5, it will be seen that such embodiment is generally analogous to the embodiment previously described in FIGS. 1 and 2, and therefore, the reference numerals used in the embodiment of FIGS. 3-5 will correspond with those previously used wherever possible. The modified incinerator will be generally designated by the reference numeral and its overall shape, eX- terior configuration, etc., correspond with the previously described embodiment, as is apparent by comparing FIGS. 3 and 4 with previously described FIGS. l and 2.

In the primary combustion chamber 36 of the ernbodiment of FIGS. 3 and 4, a hearth is provided adjacent the wall 34, such hearth consisting of a forwardly extending horizontal ledge 140 and a depending wall 142 from the forward end thereof to the base wall 30. A transversely extending passage 144 is formed within the hearth, as shown in FIG. 4. The grate 38 extends between the front wall 26 of theincinerator and the hearth. Also, the position of the main or first burner and its passage 52 can be varied from the position shown in FIG. l to that shown in FIG. 3. The entire charging hood arrangement and air blower means 66 remains identical with that previously described. However, the construction of the wall 34 is changed somewhat, as can best be seen from FIG. 5. The port 74 is provided in the upper left-har1d corner of the wall 34, when looking front to rear in the incinerator 20', instead of being provided in the upper right-hand corner as in the previously described embodiment. Thus, the products of combustion from the primary combustion chamber 36 iow through the port 74 and into the space bounded by the walls 34, 76, 82 and a portion of the side wall 24. In the previously described embodiment, this portion was the left-hand portion of the secondary combustion chamber 78. However, in this embodiment, it will be noted that no burner is provided in this space and that the wall 82 is hence not heated to an incandescent condition. Also, it will be noted that the openings 90 have been eliminated from the wall 80. As a result, the preheated air being directed into the passage 88 from the openings 114 can pass outwardly solely through the openings 90 in the wall 82. Thus, this air mixes with the products of combustion passing through the port 74 and such products of combustion and mixed preheated air then flow downwardly to pass through an opening 146 at the lower left-hand corner of the wall 34, such opening communicating with the passage 144 within the hearth.

The products of combustion and the air admixed therewith flow through the passage 144 within the hearth and exit therefrom through a port 148 formed at the lower right-hand corner of the wall 34. The second burner 118 is located along the lower portion of the side wall 24 of the incinerator 20' so that it shoots its flame through the passage 120 and into the passage 144 within the hearth. In other words, this passage 144 extending through the underside of the hearth acts as a secondary combustion chamber for burning the gases passing therethrough.

As the gases exit through the port 148 and pass from the underside of the hearth, they expand into the area formed between the solid wall 80, the side wall 22, and

the walls 34 and 76. As such gases continue to expand,

they pass through an enlarged port 124' at the upper right-hand corner of the wall 76, when looking front to rear in the modified incinerator 20'. The gases thereupon enter the tertiary combustion chamber 92 and it will be seen that the position of the burner 126 in this combustion chamber is along the right-hand wall 22 thereof, instead of along the left-hand wall as was the case with the embodiment of FIG. l. Thus, the llame from the burner 126 shoots through the opening 128 and heats the Walls 96 and 98 to an incandescent condition, as previously described. The gases thus pass through the openings 106 in these incandescent walls 96 'and 98 and admix with the preheated air being directed upwardly through the ports 116 and through the vertically extending chamber 104. Although no thermostatic control was required for the third burner 126 in the embodiment of FIGS. l and 2, such a thermostatic control can be advantageously utilized in the embodiment of FIGS. 3-5, and such a control, designated 150, is illustrated in FIG. 3.

The gases from the tertiary combustion chamber 92 then pass through an opening 130, formed at the lower left-hand side of the wall 94, when looking front to rear in the modified incinerator 20', pass through the settling chamber 132, and exit through the port 136 to the breeching. The port or opening 136 in the embodiment of FIGS. 3-5 is located in the rear wall 28, rather than in one of the side walls, such showing merely being illustrative to demonstrate that the location of this opening could be modified or changed, as desired.

It will thus be apparent that the embodiment shown in FIGS. 3-5 does not differ appreciably from that previously described in connection with FIGS. 1 and 2. Only one diffusion chamber means has its walls heated to an incandescent condition in this latter embodiment, and additionally, a hearth is provided for enabling cornbustion in a passage therebeneath, but the basic inventive aspects still remain the same.

While the present invention has been described primarily in connection with plastic materials, it should be understood that the same inventive concepts have utility in the combustion of like insulating type materials, such as mattresses, rugs, wools, and so on, and that such like materials, which have heretofore been difficult to incinerate, can be handled in the incineration apparatus described hereinbefore in the same manner as can plastic materials.

After reading the foregoing detailed description, it should be apparent that the objects set forth at the outset of the specification have been successfully achieved by the present invention. However, since the foregoing detailed description was merely directed to preferred embodiments of the invention, various changes will become apparent to those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. In an incinerator for burning a charge of plastic materials or the like, the combination comprising:

primary combustion chamber means;

secondary combustion chamber means juxtaposed to said primary combustion chamber means and communicating therewith; rst burner means for burning a charge of said materials in said primary combustion chamber means;

second burner means firing into said secondary combustion chamber means for burning the products of combustion which pass from said primary combustion chamber into said secondary combustion chamber means; and

diffusion means disposed within said secondary combustion chamber means;

said diffusion means including at least one wall having a series of spaced apart apertures therein; said second burner means being directed to re upon said wall to heat said wall to an incandescent condition whereby said products of cornbustion entering said secondary combustion chamber are initially burned -by said second burner means and are subsequently contacted against said incandescent wall to create further combustion, of the combustible constituents therein;

said diffusion means including a second wa'll juxtaposed to said one wall, said walls'being generally vertically arranged in said secondary combustion chamber means and hence defining therebetween a generally vertically extending chamber.

2. The combination dened in claim 1 wherein said secondary combustion chamber means and hence said vertically extending chamber are bounded by upper and lower generally horizontal wallswhich are heated by the combustion within said secondary combustion chamber means and wherein an air transmitting passage means is juxtaposed to one of said horizontal walls so that the air Within said passage means is heated by said one horizontal wall.

3. The combination defined in claim 2 wherein said one horizontal wall is provided with orice means which establish communication between said passage means and said vertically extending chamber thus permitting -said preheated air from said passage means to iiow into said vertically extending chamber to mix with combustion gases in said secondary combustion chamber via said spaced apart apertures.

4. The combination defined in claim 3 wherein said i second wall is provided with a series of spaced apart aperture means similar to those in said one wall, and wherein said walls and said vertically extending chamber therebetween are arranged generally medially of said secondary combustion chamber means.

5. The combination defined in claim 4 further including:

tertiary combustion chamber means juxtaposed to and communicating with said secondary combustion chamber means; diffusion chamber means disposed medially of said tertiary combustion chamber means, said diffusion chamber means including a pair of spaced apart vertically extending walls, each having a series of spaced apart apertures therein; said pair of Walls thus delining therebetween a further vertically extending chamber; one of said horizontal walls including further orice means establishing communication between said air passage means and further vertically extending chamber to admit preheated air to mix with the combustion gases in said tertiary combustion chamber means; and third burner means firing into said tertiary combustion chamber means for burning the products of combustion passing from said secondary combustion chamber means into said tertiary combustion chamber means; said third burner means being directed to fire upon at least one of the walls of said diffusion chamber means to heat at least said one wall to an incandescent condition. 6. In an incinerator for burning a charge of plastic materials or the like, the combination comprising:

primary combustion chamber means; secondary combustion chamber means juxtaposed to said primary combustion chamber means and communicating therewith; iirst burner means for burning a charge of said materials in said primary combustion chamber means; second burner means Ifiring into said secondary combustion chamber means for burning the products of combustion which pass from said primary combustion chamber into said secondary combustion chamber means;

diffusion means disposed within said secondary combustion chamber means; said diffusion means including at least one wall having a series of spaced apart apertures therein;

said second burner means being directed to lire upon said wall to heat said wall to an incandescent condition whereby said products of combustion entering said secondary combustion chamber are initially burned by said second burner means and are subsequently contacted against said incandescent wall to create further combustion of the combustible constituents therein; and

hearth means in said primary combustion chamber means, said hearth means having a transversely extending passage therethrough detining an intermediate combustion chamber means between said primary and secondary combustion chamber means, additional burner means tiring into said intermediate combustion chamber means, and means dening an entrance port andan exit port at opposite ends of said intermediate combustion chamber means.

7. The combination defined in claim l6 further including supplemental chamber means and means for admitting preheated air into said supplemental chamber means, said primary combustion, secondary combustion, intermediate combustion and supplemental chamber means being positioned so that the products of combustion from said primary combustion chamber means pass first into said supplemental chamber means to mix with the preheated air therein, then pass through said entrance port into and through said intermediate chamber where they are burned by said additional burner means, and nally pass through said exit port and into said secondary combustion chamber means.

8. In an incinerator for burning a charge of plastic materials or the like, the combination comprising:

primary combustion chamber means;

secondary combustion chamber means juxtaposed to said primary combustion chamber means and cornmunicating therewith; rst burner means for burning a charge of said materials in said primary combustion chamber means;

second burner means firing into said secondary combustion chamber means for burning the products of combustion which pass from said primary combustion chamber into said secondary combustion chamber means;

diffusion means disposed within said secondary cornbustion chamber means; said diffusion means including at least one wall having a series of spaced apart apertures therein;

said second burner means being directed to -fire upon said wall to heat said Wall to an incandescent condition whereby said products of combustion entering said ysecondary combustion chamber are initially burned by said second burner means and are subsequently contacted against said incandescent wall to create further combustion of the combustible constituents therein; and

means defining a charging port in said primary combustion chamber means, charging hopper means projecting forwardly from said primary combustion chamber means and a closure means normally closing said hopper -means at a location spaced forwardly from said charging port, said closure means being openable to permit said charge of materials to be introduced into and through said hopper means and said charging port to enter said primary combustion chamber means for burning therein.

9. The combination dened in claim 8 further including means supplying a quantity of air to said hopper means intermediate said closure means and said charging port, said quantity of air preventing smoke and odors from escaping from said primary combustion chamber means when said closure means is opened.

10. The combination dened in claim 9 wherein said means supplying a quantity of air includes:

passage means juxtaposed to at least one wall of said primary combustion chamber means; flow producing means for creating an air ow through said passage means to cause said air to be preheated by contact with said primary combustion chamber means; conduit means for directing said air from said passage means to said hopper means; and orice means through said hopper means whereby said air from said conduit means enters said hopper means and thereafter flows into said primary combustion chamber means. 11. The combination defined in claim 10 wherein said passage means includes at least one aperture opening directly into said primary combustion chamber means so that at least a portion of said air liow through said passage means passes directly into said primary combustion chamber means.

References Cited UNITED STATES PATENTS 1,070,209 8/ 1913 Thorpe et al. 2,988,023 6/ 1961 Osswald. 3,079,878 3/1963 Vargo et al.

FOREIGN PATENTS 944,480 12/ 1963 Great Britain.

15 CHARLES J. MYHRE, Primary Examiner U,S. Cl. X.R. 110-22 

